Hong Kong’s police was set up in 1844, just three years after the British took over the city, and the force calls itself one of Asia’s oldest. For years, the force was riddled with corruption, with officers at all levels known to accept payoffs for everything from protecting shops and restaurants to syndicates of bribe-takers in every police station. In 1974, the British colonial government set up a watchdog called the Independent Commission Against Corruption, and since then the graft-busting agency, which is still active, has kept the city and many of its businesses in check.

Images of the police in Sunday’s crackdown, however, have tarnished the force’s image. The Hong Kong government has repeatedly called the rallies illegal, echoing Beijing’s stance, and said Friday that “nonsensical acts of obstructing the police and other public officers carrying out their duties to serve the community will not be tolerated.”